1. Field of the Invention
The present invention relates to a light source device, and more particularly, to a fiber-based light source device where the fiber is for guiding the light, for providing a uniform light source.
2. Description of the Prior Art
With the electro-optical transfer efficiency and strength of modern semiconductor light-emitting devices gradually increasing plus prevalence of the concept of environment protection/preservation, the demand for electronic devices with lower power consumption is continuing to increase. Because semiconductor light-emitting devices are low power in nature that meet the trend, therefore are widely used as parts of a variety of light sources. The incorporation of semiconductor light-emitting devices with fiber-based light guiding technology renders light beams outputted from semiconductor light-emitting devices then are mixed and go through the fiber to make a light source based on electronic devices possible. For example, a projector employs the fiber-based light guiding technology to generate a light, which is the product of light beams generated by semiconductor light-emitting devices, as its light source for projection.
Please refer to FIG. 1 of a schematic diagram showing the structure of a prior art laser light source, titled as “fiber connecting method, laser apparatus and projection television” based on U.S. Pat. No. 6,954,571. The laser light source according to this prior art couples a plurality of laser light beams to a single-core fiber to form a coupled light source. A first laser generator 21, a second laser generator 22, a third laser generator 23, a fourth laser generator 24, a fifth laser generator 25, a sixth laser generator 26, and a seventh laser generator 27 generate a laser beam, respectively. The first laser generator 21 couples with a first light guiding device 31, the second laser generator 22 couples with a second light guiding device 32, the third laser generator 23 couples with a third light guiding device 33, the fourth laser generator 24 couples with a fourth light guiding device 34, the fifth laser generator 25 couples with a fifth laser guiding device 35, the sixth laser generator 26 couples with a sixth light guiding device 36, and the seventh laser generator 27 couples with a seventh light guiding device 37.
The first light guiding device 31 further couples with a first fiber 41, the second light guiding device 32 couples with a second fiber, the third light guiding device 33 couples with a third fiber 43, the fourth light guiding device 34 couples with a fourth fiber 44, the fifth light guiding device 35 couples with a fifth fiber 45, the sixth light guiding device 36 couples with a sixth finer 46, and the seventh light guiding device 37 couples with a seventh fiber 47. The first, second, third, fourth, fifth, sixth, and seventh fibers all connect to a coupling device 50. While each light guiding device guides its respective laser beam to the corresponding fiber, the coupling device 50 couples all light beams and outputs to a single-core fiber in order to mix all light beams together to form a coupled point light.
As a result, the output end of the single-core fiber outputs a quality point light source and through a condenser all point light sources from all single-core fibers could form a uniform light source, or other light sources as expected. Light beams in different colors could be mixed into a white light or lights in other colors in a single-core fiber without color deviations stemming from observing from different angles. However the energy of the light beams attenuates at the time of coupling. The more light beams of fibers are coupled into the single-core fiber, the more energy loss would take place. The energy loss for each fiber is estimated to be 0.5 dB while the directional coupler leads to 0.15 dB energy losses. Consequently, the total energy loss for the laser light source would be 3.5 dB.